In conventional motor vehicles, power take-off (PTO) and cruise control may be common features used in vehicle powertrain management. PTO has been used to provide power to up-fitter installed accessories, for example a bucket lift, also referred to as “cherry picker”, a snow plow, a dump body, etc. PTO is a mechanism or technique, such as using a gearbox or bolt-on attachment, of driving a pump to supply power necessary to provide a function. Examples of common PTO applications include lifting or manipulating a dump body, a bucket lift, or a snow plow. Cruise control is a feature that permits a vehicle user to set and vary the speed of a vehicle.
Current cruise enable, or cruise on/off, switch configurations typically consist of an unasserted low or inactive state, such as a 0 Volts, and an asserted high or active state, such as a vehicle battery voltage. Alternatively, cruise enable switches may consist of an unasserted high or inactive state, such as vehicle battery voltage, and an asserted low or active state, such as 0 Volts. The alternative configuration is generally not used because of an undesirable failure mode. In a similar fashion to typical cruise enable switches, current PTO enable, or PTO on/off, switch configurations consist of an unasserted low or inactive state, such as 0 Volts, and an asserted high or active state, such as vehicle battery voltage.
Additionally, conventional cruise enable may be implemented within a 5 Volt range for cruise control where a portion thereof is allocated to cruise enable. For example, the 5 Volt range may be divided into 9 potential states from a 5 Volt analog input such that: a first potential state is corresponds to a short to battery; a second potential state corresponds to cruise enable; a third potential state corresponds to a dead-band between cruise enable and set/coast; a fourth potential state corresponds to set/coast; a fifth potential state corresponds to a dead-band between set/coast and resume/accelerate; a sixth potential state corresponds to resume/accelerate; a seventh potential state corresponds to a dead-band between resume/accelerate and cruise cancel; an eight potential state corresponds to cruise cancel; and, a ninth potential state corresponds to a short to ground or open circuit.
Compliance with probability of occurrence metrics is generally required to meet safety and performance requirements of various motor vehicle components. One concern with vehicle control devices is in improving failure modes and a desire to diagnose circuit conditions of such devices. For example, the single input cruise enable and PTO enable switches, previously mentioned hereinabove, do not readily provide adequate diagnosing for either an open circuit condition, such as a short to ground, or a short to battery condition because such conditions represent the enabled states of the switches. Although potential states of the 5 Volt based analog cruise control switch, previously mentioned hereinabove, are designated to indicate circuit conditions, sophisticated algorithm for operation and stringent part tolerances (e.g., for resistors) are typically required to implement the various potential states.
Accordingly, it is desirable to provide an enable switch for motor vehicle powertrain applications that reduces the probability of failure occurrence. In addition, it is desirable to provide a PTO and cruise enable that is simple to implement and assists in servicing procedures of the motor vehicle. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description of the invention and the appended claims, taken in conjunction with the accompanying drawings and this background of the invention.